This invention relates generally to a method of making a milk-like beverage from soy beans, and more particularly to such a method which utilizes substantially all of the bean mass and results in the production of such a beverage with the appearance, taste and mouthfeel of homogenized natural milk.
It has long been known that soy beans possess proteinaceous, fatty, carbohydrate, and other, values that make them a prime raw material source for the preparation of various food items, including beverages, of which perhaps the principal example is a milk-like beverage often referred to as soy, or soya, milk. For centuries soy milk has been made from soy beans in the far East by a fairly simple process of forming an emulsion from the extracted fat and protein components of the beans. While this beverage has apparently been acceptable to the Oriental palate, Western man has found the flavor unpleasant, if not nauseous. However, the food value of soy milk is high, and for this reason many attempts have been made, over a great many years, to come up with a process of obtaining soy milk absent the unpleasant "soy" or "beany" taste so unpleasant to Westerners. All such processes of which we are aware involve the necessary removal of some of the nutritional components of soy beans and include various cooking, chemical treating, etc., steps to convert the beans to aqueous solution, or the like, form, mask or remove the beany taste in the final product, and provide a beverage as nearly as possible like real milk in taste and other qualities.
In certain instances, the de-oiled products of soy beans, and in other instances modified forms of the beans, such as, for example, full fat bean flakes, or bean flour, have been employed as starting materials for the production of soy milk. Regardless of the nature of the starting material, however, some of the soy bean mass, in certain cases in solid, and in other cases in liquified (whey) form, is always, to our knowledge, discarded or otherwise disposed of in the production of soy milk therefrom. This, of course, reduces the percentage of recovery of the starting material in the final product, and thereby increases the cost of that product.
As an indication of the many efforts to economically produce soy bean milk suited to the Western taste, various processes have, to our knowledge, been patented at least from as early as 1915 (U.S. Pat. No. 1,165,199 to Monahan et al.), to as late as May 1974 (U.S. Pat. No. 3,809,771 to Mustakas). One such patented process (U.S. Pat. No. 3,642,492 to Arndt) employs a mixture of sweet dairy whey and isolated soy protein which has been treated by a "dynamic physico-thermovapor flash treatment to remove objectionable flavors and odors." Another patented process (U.S. Pat. No. 3,288,614 to Miles) involves a number of treating steps including the homogenization of an "instant" slurry of flaked beans to avoid the bacterial contamination which allegedly takes place in an earlier process described in the patent in which a considerable percentage of the "finer edible content of the soy bean" is lost through discard with the "coarser fibers removed" in a centrifuging step of that (earlier) process. The latter patent claims a saving in raw material by comparison with said earlier process, but Miles' process still yields a slurry which is "clarified" in a centrifugal separator with resultant loss of the solid residue from that operation.
Those skilled in the art will readily appreciate that, as indicated above, presently known methods of producing soy milk involve numerous treating steps, some for the reduction, masking or elimination of the characteristically unpleasant beany taste of soy beans, and result in the recovery of only a part of the soy bean nutritive, and other, values with consequent waste of the remaining values and inflation of the selling price of the final product. Sometimes as much as 65 percent of the soy bean mass is lost to waste in soy milk producing processes heretofore known.
Since essentially the whole soy bean can be theoretically utilized for its nutritive, and other useful, values, so long as its beany taste can be eliminated in a harmless way without destruction of the food value of the bean, some way of converting the whole bean into pleasant tasting soy milk would be extremely useful, particularly in this modern era of emphasis on the use of health foods derived from natural vegetable sources.